In the past, an outer surface of an electrically conductive body has been covered with an electrochemically applied metal, a mechanically applied metal foil, or mechanically applied metal cap, in order to make the electrically conductive body wear resistant. Such combinations are taught in U.S. Pat. Nos. 4,104,109 and 5,161,667.
The present invention relates to a wear resistant electrically conductive body. The outer surface of the electrically conductive body has an ion-accelerated, wear-resistant, electrically conductive diamond-like carbon coating. The outer surface of the electrically conductive body is formed by the electrically conductive diamond-like carbon coating.
The present invention relates to a method for forming the ion-accelerated, wear-resistant, electrically conductive diamond-like carbon coating on the electrically conductive body. The resultant outer surface of the electrically conductive body is an ion-formed diamond-like surface
The electrically conductive diamond-like carbon coating is a combination of amorphous diamond-like carbon material and electrically conductive metal material. The conductivity of the outer surface will benefit from graphitic characteristics of the amorphous diamond-like carbon material. That is, the higher the percentage of graphite in the amorphous diamond-like carbon material, the greater the conductivity of the diamond-like carbon coating. However, the percentage of graphite in the amorphous diamond-like carbon material must be controlled, in order to avoid excessive graphitic characteristics.
An ion beam process, such as a dual ion beam process, is used to form the coating. A dual ion beam process is used to coat an electrically conductive body with the electrically conductive diamond-like carbon coating.
The graphite component of the electrically conductive diamond-like carbon coating can be controlled, percentage-wise, by adjusting conditions of the coating process By adjusting a carbon ion beam intensity of carbon ions that are being applied to the electrically conductive body, applied carbon atoms are held in an intermediate reactive state. The carbon atoms will stabilize, by oxidation, into a resonance-stabilized, covalent structure of an aromatic graphite structure.
The outer surface of an electrically conductive body, such as a copper slip ring, is covered by an ion-accelerated, wear-resistant, electrically conductive coating that contains diamond-like carbon atoms and electrically conductive metal atoms. A wear-resistant electrically conductive body is produced. The produced wear-resistant electrically conductive body is a combination of an electrically conductive body and an ion-accelerated, wear-resistant, electrically conductive coating. Ion-accelerated diamond-like carbon atoms and ion-accelerated metal atoms form the ion-accelerated, wear-resistant, electrically conductive coating. The ion-accelerated, wear-resistant, electrically conductive coating covers an outer surface of the wear-resistant electrically conductive body. The coating causes the wear resistant electrically conductive body to be both electrically conductive and wear resistant.
The ion-accelerated metal atoms of the disclosed ion-accelerated, wear-resistant, electrically conductive coating form contiguous conductive chains of metal atoms. The ion-accelerated, wear-resistant, electrically conductive coating contains contiguous metal atoms, such as contiguous copper atoms. The contiguous metal atoms cause the ion-accelerated wear-resistant conductive coating to be electrically conductive from one side of the coating to the other side of the coating.
The ion-accelerated, wear-resistant, electrically conductive coating of the disclosed wear-resistant conductive body contains ion-accelerated diamond-like carbon atoms. The ion-accelerated diamond-like carbon atoms cause the wear-resistant conductive coating to be wear resistant.
The ion accelerated, wear-resistant, electrically conductive coating is formed by simultaneously ion-accelerating both metal ions, such as copper ions, and diamond-like carbon ions onto the outer surface of an electrically conductive body, such as an ordinary motor slip ring. The copper ions and diamond-like carbon ions are electrically attracted to the electrically conductive body within an ion accelerator.
An ion sprayer is shown in U.S. Pat. No. 6,086,962. U.S. Pat. No. 6,086,962 discloses a method of spraying diamond-like carbon ions and non-conductive silicon ions onto an electrically nonconductive surface. The teachings of U.S. Pat. No. 6,086,962 are incorporated herein by reference.
In the method of the present invention, metal ions, such as copper ions, and diamond-like carbon ions are simultaneously ion-accelerated onto an outer surface of an electrically conductive body, such as an ordinary motor slip ring. A negative voltage is applied to the conductive body. The negative voltage causes the ions to accelerate toward the conductive body.
In the '962 patent, silicon ions and diamond-like carbon ions are sprayed onto an electrically nonconductive body, as the ions accelerate toward cathode. The '962 patent does not suggest simultaneously ion-accelerating metal ions and diamond like carbon ions toward an electrically conductive body, in order to form an wear-resistant electrically conductive coating on the electrically conductive body.
By the method of the present invention, copper ions and diamond-like carbon ions are accelerated onto an electrically conductive body. Copper ions from the ion accelerator are attracted to the electrically conductive body by electrons that are on the electrically conductive body. As the copper ions impinge the electrically conductive body, the copper ions are electrically neutralized by electrons that are located on the electrically conductive body. Copper atoms, that is, neutralized copper ions, are formed on the electrically conductive body. These copper atoms then conduct other electrons from the electrically conductive body. These other electrons attract copper ions toward the copper atoms. A chains of copper atoms is formed. Chains of copper atoms are built up on the electrically conductive body.
The advantages of using an ion-accelerated, wear-resistant conductive coating on a conductive body are enhancement of wear resistance, reduction of contact friction, preservation of surface contact conductivity and preservation of surface finish.